scholarly journals Electrochemical Passivation Properties of Valve Transition Metal Carbides

2022 ◽  
Author(s):  
Daniel Goehl ◽  
Holger Rueß ◽  
Andrea M Mingers ◽  
Karl Johann Jakob Mayrhofer ◽  
Jochen M Schneider ◽  
...  
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Polymer Electrolyte Membrane ◽  
Catalyst Support ◽  
Tantalum Carbide ◽  
Metal Carbides ◽  
Support Materials ◽  
Transition Metal Carbides ◽  
Electrochemical Passivation

Abstract Transition metal carbides have the potential to be employed as corrosion protective coating for a variety of applications such as e.g. steel based bipolar plates, porous transport layers or as catalyst support in polymer electrolyte membrane fuel cells and water electrolyzers. Yet, little is known of their fundamental, intrinsic corrosion and passivation properties. Herein, we conducted a detailed electrochemical passivation study of various valve transition metal carbides such as titanium carbide, tantalum carbide or tungsten carbide. Via flow cell measurements coupled to an inductively coupled plasma mass spectrometer, the in-situ transition metal dissolution was monitored, and the faradaic dissolution efficiency was calculated. Together with the determination of the grown oxide layer via X-ray photoelectron spectroscopy, a thorough evaluation of the passivation efficiency was conducted. Moreover, it was shown that a beneficial stabilization effect can be achieved through alloying of different carbides, which paves the way towards tailor-made coatings or catalyst support materials.

DMFCs with Enhanced Catalytic Activity and Durability Using Transition-Metal Carbides as Catalyst Support

2019 ◽  
Vol 33 (1) ◽  
pp. 2027-2034 ◽  
Author(s):  
K.G. Nishanth ◽  
P. Sridhar ◽  
S. Pitchumani ◽  
Ashok Shukla
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Catalyst Support ◽  
Metal Carbides ◽  
Transition Metal Carbides

The crystal structure and phase stability of the zeta phase in the group VB transition metal carbides: a computational investigation

2019 ◽  
Vol 75 (5) ◽  
pp. 870-879 ◽  
Author(s):  
Christopher R. Weinberger ◽  
Gregory B. Thompson
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Phase Stability ◽  
Density Functional ◽  
Computational Study ◽  
Equilibrium Phase ◽  
Tantalum Carbide ◽  
High Fracture Toughness ◽  
Metal Carbides ◽  
Transition Metal Carbides

The crystal structure and composition of the zeta phase in the group VB transition metal carbides are not completely understood despite decades of experimental studies. As such, the phase rarely appears on phase diagrams of the group VB transition metal carbides. There is currently renewed interest in this phase, as tantalum carbide composites exhibit high fracture toughness in the presence of this phase. This work extends the initial computational study using density functional theory of the phase stability of the zeta phase in the tantalum carbide system, where the tantalum carbide zeta-phase crystal structure and stability were determined, to the niobium and vanadium carbides. It is shown that the zeta phases in the three systems share the same crystal structure and it is an equilibrium phase at low temperatures. The carbon atom ordering in the three different phases is explored and it is demonstrated that the zeta phase in the tantalum carbides prefers to order carbon atoms differently than in the niobium and vanadium carbide zeta phases. Finally, the properties of this crystal are computed, including elastic constants, electronic densities of states and phonon dispersion curves, to illustrate that this crystal structure is similar to other transition metal carbides.

scholarly journals X-ray photoelectron spectroscopy of select multi-layered transition metal carbides (MXenes)

2016 ◽  
Vol 362 ◽  
pp. 406-417 ◽  
Author(s):  
Joseph Halim ◽  
Kevin M. Cook ◽  
Michael Naguib ◽  
Per Eklund ◽  
Yury Gogotsi ◽  
...  
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Metal Carbides ◽  
X Ray ◽  
Transition Metal Carbides ◽  
Layered Transition Metal

Tuning Transition Metal Carbides Activity by Surface Metal Alloying: Case Study on CO2 Capture and Activation

2018 ◽  
Author(s):  
Marti Lopez ◽  
Luke Broderick ◽  
John J Carey ◽  
Francesc Vines ◽  
Michael Nolan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Co2 Capture ◽  
Density Functional ◽  
Deep Understanding ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Adsorption Sites ◽  
Surface Metal ◽  
A Minor

<div>CO2 is one of the main actors in the greenhouse effect and its removal from the atmosphere is becoming an urgent need. Thus, CO2 capture and storage (CCS) and CO2 capture and usage (CCU) technologies are intensively investigated as technologies to decrease the concentration</div><div>of atmospheric CO2. Both CCS and CCU require appropriate materials to adsorb/release and adsorb/activate CO2, respectively. Recently, it has been theoretically and experimentally shown that transition metal carbides (TMC) are able to capture, store, and activate CO2. To further improve the adsorption capacity of these materials, a deep understanding of the atomic level processes involved is essential. In the present work, we theoretically investigate the possible effects of surface metal doping of these TMCs by taking TiC as a textbook case and Cr, Hf, Mo, Nb, Ta, V, W, and Zr as dopants. Using periodic slab models with large</div><div>supercells and state-of-the-art density functional theory based calculations we show that CO2 adsorption is enhanced by doping with metals down a group but worsened along the d series. Adsorption sites, dispersion and coverage appear to play a minor, secondary constant effect. The dopant-induced adsorption enhancement is highly biased by the charge rearrangement at the surface. In all cases, CO2 activation is found but doping can shift the desorption temperature by up to 135 K.</div>

scholarly journals Predicting the Effect of Dopants on CO2 Adsorption in Transition Metal Carbides: Case Study on TiC (001)

2020 ◽  
Vol 124 (29) ◽  
pp. 15969-15976 ◽  
Author(s):  
Martí López ◽  
Francesc Viñes ◽  
Michael Nolan ◽  
Francesc Illas
Keyword(s):  
Transition Metal ◽  
Co2 Adsorption ◽  
Metal Carbides ◽  
Transition Metal Carbides
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